WO2021065258A1 - Diamond rod, diamond tool, and cantilever - Google Patents

Abstract

The diamond rod is a diamond rod comprising a CVD single crystal diamond, wherein the diamond rod has a length L in the longitudinal direction of 2-20 mm inclusive and, when the cross-section having the minimum area of the cross-sections that appear when the diamond rod is cut in a plane perpendicular to the longitudinal direction is taken to be the first cross-section, the ratio L/W of the length L to the maximum width W in the first cross-section is 10 to 30 inclusive.

Description

Diamond rods, diamond tools and cantilever

This disclosure relates to diamond rods, diamond tools and cantilever. This application claims priority based on Japanese Patent Application No. 2019-181349 filed on October 1, 2019. All the contents of the Japanese patent application are incorporated herein by reference.

As single crystal diamonds used as materials for cutting tools, abrasion resistant tools, etc., artificial diamonds manufactured by a high temperature and high pressure synthesis (HPHT: High Pressure and High Temperature) method are widely used rather than natural diamonds. The reason is that synthetic diamonds are more stable in quality and supply than natural diamonds. However, artificial diamond produced by the high-temperature and high-pressure synthesis method has a high demand for cost reduction because the cost of the production equipment is high. On the other hand, as an artificial diamond produced by another synthetic method, a single crystal diamond produced by a chemical vapor deposition (CVD) method (hereinafter, also referred to as "CVD single crystal diamond") is known. However, when CVD single crystal diamond is used as a tool material, it is said that defects such as chips and cracks are likely to occur.

On the other hand, International Publication No. 2014/168053 (Patent Document 1) makes use of the characteristic of CVD single crystal diamond that impurities and crystal defects are easily introduced by controlling them, thereby causing defects such as chips and cracks. The suppressed CVD single crystal diamond is disclosed.

International Publication No. 2014/168053

The diamond rod-shaped body according to the present disclosure is a diamond rod-shaped body made of CVD single crystal diamond, the diamond rod-shaped body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less, and the diamond rod-shaped body is described above. When the cross section having the minimum area is defined as the first cross section among the cross sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction, the ratio of the length L to the maximum width W in the first cross section. L / W is 10 or more and 30 or less.

The diamond tool according to the present disclosure is a diamond tool including a base metal portion and a diamond portion joined to the base metal portion, and the diamond portion is made of the diamond rod-shaped body.

The cantilever according to the present disclosure is made of the above diamond rod-shaped body.

[Issues to be solved by this disclosure]
In recent years, thickening has been progressing in work materials such as non-ferrous metals and resins (hereinafter, also referred to as "work"), which are processed by cutting tools using single crystal diamond. Therefore, there is a demand for a cutting tool having a high aspect ratio in which the ratio of the length of the cutting tool in the longitudinal direction to the width of the cross section obtained by cutting the cutting tool in a plane perpendicular to the longitudinal direction is large. There is. However, since the strength of the work is increasing in parallel with the thickening, the cutting tool having a high aspect ratio tends to break easily and the life of the tool tends to be shortened. Patent Document 1 discloses a technique for suppressing the occurrence of defects such as chips and cracks in a CVD single crystal diamond, but does not describe suppressing breakage in a shape having a high aspect ratio. Therefore, in a cutting tool containing CVD single crystal diamond, it is desired to develop a cutting tool in which breakage is suppressed even when it has a high aspect ratio and thus a long life is realized.

In view of the above circumstances, it is an object of the present disclosure to provide a diamond rod, a diamond tool and a cantilever that can achieve a long life.

[Effect of the present disclosure]
According to the present disclosure, it is possible to provide a diamond rod, a diamond tool and a cantilever that can achieve a long life.

[Explanation of Embodiments of the present disclosure]
The present inventors have completed the present disclosure by repeating diligent studies in order to solve the above problems. Specifically, it has been found that by appropriately controlling impurities and crystal defects introduced into a CVD single crystal diamond, a CVD single crystal diamond in which breakage is suppressed even when it has a high aspect ratio can be obtained. .. By applying this CVD single crystal diamond as a tool material, we have come up with a diamond rod and a diamond tool that can extend the life of the tool even when it has a high aspect ratio, and have reached the present disclosure. It was also found that the cantilever made of the diamond rod-like body improves the quality of the sound picked up from the sound groove of the record.

First, embodiments of the present disclosure will be listed and described.
[1] The diamond rod-shaped body according to one aspect of the present disclosure is a diamond rod-shaped body made of CVD single crystal diamond, and the diamond rod-shaped body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less, and is described above. The diamond rod-shaped body has a cross section that appears by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction, and when the cross section having the minimum area is the first cross section, the maximum width W in the first cross section is obtained. The ratio L / W of the length L is 10 or more and 30 or less. A diamond rod-shaped body having such characteristics can suppress breakage of the tool even when a tool having a high aspect ratio is formed by applying the diamond rod-shaped body as a tool material. A long life can be realized.

[2] The average atomic concentration of nitrogen contained in the CVD single crystal diamond is preferably 1 ppm or more and 100 ppm or less. As a result, even when a tool having a high aspect ratio is formed by applying the diamond rod-shaped body as a tool material, breakage of the tool can be more sufficiently suppressed, and thus the life of the tool is extended. Can be realized.

[3] The CVD single crystal diamond has an average value of a phase difference of 1 nm or more and 200 nm or less, and the phase difference is a phase difference generated when the CVD single crystal diamond is irradiated with circular polarization. Is preferable. As a result, even when a tool having a high aspect ratio is formed by applying the diamond rod-shaped body as a tool material, breakage of the tool can be more sufficiently suppressed, and thus the life of the tool is extended. Can be realized.

[4] The diamond tool according to one aspect of the present disclosure is a diamond tool including a base metal portion and a diamond portion joined to the base metal portion, and the diamond portion is composed of the diamond rod-shaped body. Is preferable. A diamond tool having such a feature can suppress breakage even when it has a high aspect ratio, and thus can realize a long life.

[5] The diamond tool is preferably a drill. As a result, even when the drill has a high aspect ratio, breakage can be suppressed, and a long life can be realized.

[6] The cantilever according to one aspect of the present disclosure is made of the diamond rod-shaped body. A cantilever having such a feature can suppress breakage even when it has a high aspect ratio, and can improve the quality of the sound picked up from the sound groove of the record.

[7] The cantilever preferably contains a stylus. As a result, the quality of the sound picked up from the sound groove of the record can be further improved.

[Details of Embodiments of the present disclosure]
Hereinafter, embodiments of the present disclosure (hereinafter, also referred to as “the present embodiments”) will be described in more detail. Here, in the present specification, the notation in the form of "A to B" means the upper and lower limits of the range (that is, A or more and B or less), and the unit is not described in A and the unit is described only in B. , The unit of A and the unit of B are the same.

[Diamond rod]
The diamond rod-shaped body according to the present embodiment is a diamond rod-shaped body made of CVD single crystal diamond. The diamond rod-shaped body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less. Further, the diamond rod-shaped body has the maximum width in the first cross section when the cross section having the smallest area is defined as the first cross section among the cross sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction. The ratio L / W of the length L to W is 10 or more and 30 or less.

When a diamond rod having such characteristics is applied as a tool material, the work is processed as a tool having a CVD single crystal diamond having a high aspect ratio (that is, a ratio L / W of 10 or more and 30 or less). Even so, breakage can be suppressed. Therefore, the diamond rod-shaped body can extend the life of the tool including the diamond rod-shaped body.

<CVD single crystal diamond>
The diamond rod is made of CVD single crystal diamond. The CVD single crystal diamond means a single crystal diamond produced by epitaxially growing a single crystal diamond layer on a substrate made of the single crystal diamond by using a chemical vapor deposition (CVD) method. As for the method for obtaining such a CVD single crystal diamond, for example, the item described later about the method for producing a diamond rod can be referred to.

(Average atomic concentration of nitrogen)
The average atomic concentration of nitrogen contained in the CVD single crystal diamond is preferably 1 ppm or more and 100 ppm or less. As a result, even when a tool having a high aspect ratio is formed by applying the diamond rod-shaped body as a tool material, breakage of the tool can be more sufficiently suppressed. When the average atomic concentration of nitrogen is less than 1 ppm, the cleavage property, which is one of the properties of single crystal diamond, appears strongly, so cracks tend to occur when an impact is applied to a specific surface (cleavage surface). There is. If the average atomic concentration of nitrogen exceeds 100 ppm, it becomes difficult to provide the CVD single crystal diamond with desired toughness, and there is a risk that breakage of the tool cannot be sufficiently suppressed. The average atomic concentration of nitrogen in the CVD single crystal diamond is more preferably 20 ppm or more and 50 ppm or less.

The method for measuring the average atomic concentration of nitrogen in CVD single crystal diamond is as follows. That is, the atomic concentration of nitrogen in the CVD single crystal diamond can be measured by a secondary ion mass spectrometry (SIMS) method. As the measuring device, for example, a SIMS device (trade name: "IMS 7f", manufactured by CAMECA) can be used.

In measuring the atomic concentration of nitrogen in a CVD single crystal diamond, for example, based on the method for producing a diamond rod described later, a CVD single crystal diamond is first obtained to obtain a sample having a length of 2 mm or more and 20 mm or less in the longitudinal direction. To make. Next, a surface having a depth of 0.5 μm from the outermost surface of this sample is exposed by sputtering to obtain a measurement target surface of the sample. The atomic concentration of nitrogen on the surface to be measured can be determined by irradiating the surface to be measured with ^{Cs +} as a primary ion as a primary ion under the conditions of an acceleration voltage of 15 kV and a detection region of 35 μmφ. ..

The atomic concentration of nitrogen is quantified by comparison with a separately prepared standard sample (single crystal diamond with a known atomic concentration of nitrogen prepared by ion implantation). If the value of the impurity concentration is small, the measured value may deviate from the true value depending on the accuracy of the measuring device. Therefore, from the viewpoint of obtaining more accurate values, the depth from the outermost surface is deepened at a total of three locations including two locations at one end and the other end in the longitudinal direction of the sample and one location at the center portion in the longitudinal direction. It is preferable to obtain a measurement target surface having a size of 0.5 μm, calculate the average value of the measured values obtained at these three measurement target surfaces, and obtain this average value as the average atomic concentration of nitrogen.

(Phase difference: Distortion caused by crystal defects)
The CVD single crystal diamond preferably has an average value of phase difference of 1 nm or more and 200 nm or less. The phase difference means the phase difference generated when the CVD single crystal diamond is irradiated with circularly polarized light. The above phase difference occurs when crystal defects are present in the CVD single crystal diamond. That is, the phase difference is an index showing the magnitude of distortion caused by crystal defects in the CVD single crystal diamond. When the average value of the phase difference of the CVD single crystal diamond is 1 nm or more and 200 nm or less, the magnitude of the strain caused by the crystal defects in the CVD single crystal diamond is convenient for improving the toughness. Therefore, by applying the diamond rod-shaped body made of the CVD single crystal diamond as a tool material, breakage of the tool can be more sufficiently suppressed even when a tool having a high aspect ratio is formed. ..

When the average value of the above phase difference is less than 1 nm, the cleavage property, which is one of the properties of single crystal diamond, appears strongly, so that cracks are likely to occur when an impact is applied to a specific surface (cleavage surface). Tend. When the average value of the phase difference exceeds 200 nm, it becomes difficult to provide the CVD single crystal diamond with the desired toughness, and there is a risk that breakage cannot be sufficiently suppressed. The phase difference is more preferably 50 nm or more and 100 nm or less.

The average value of the phase difference in the CVD single crystal diamond can be measured by following the procedures (a-1) to (a-3) below.

(A-1) Preparation of Measurement Sample For example, based on the method for producing a diamond rod-shaped body described later, a CVD single crystal diamond is first obtained to have a length of 3 to 50 mm in the longitudinal direction, which is perpendicular to the longitudinal direction. A rectangular parallelepiped sample having a length of 1 to 5 mm in the above direction and a thickness of 700 μm or more is prepared. Next, by performing polishing, etching, etc. on the above sample, a measurement sample having a thickness of 700 μm is obtained. If the thickness of the measurement cannot be reduced to 700 μm, the phase difference can be measured with respect to the sample by the following measurement method, and then the measured value can be converted to the case where the thickness is 700 μm.

(A-2) Irradiation of circularly polarized light Circularly polarized light is irradiated to one main surface of the measurement sample prepared in the above (a-1) substantially perpendicularly. Circularly polarized light can be formed by a laser provided in a measuring device described later.

(A-3) Measurement of Birefringence Index 10 measurement areas (1 mm × 1 mm) are set on the main surface irradiated with circularly polarized light, and the phase difference is measured in these 10 measurement areas. A birefringence distribution measuring device (trade name: "WPA-100", manufactured by Photonic Lattice Co., Ltd.) can be used for measuring the phase difference. Since the measuring device includes lasers of three types of wavelengths (523 nm, 543 nm and 575 nm), the phase difference measurement range can be expanded by properly using these lasers. From the above, the measured values in the measurement region of 10 points can be obtained, and the average value can be calculated as the average value of the phase difference of the CVD single crystal diamond.

<Length L in the longitudinal direction>
The diamond rod-shaped body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less. When the length L in the longitudinal direction is 2 mm or more and 20 mm or less, the diamond rod-shaped body is broken even when a tool having a high aspect ratio is formed by applying this as a tool material. Can be suppressed. The length L of the diamond rod in the longitudinal direction is preferably 5 mm or more and 15 mm or less, and more preferably 8 mm or more and 15 mm or less. The length L of the diamond rod in the longitudinal direction can be measured by using a conventionally known length measuring device such as a caliper.

The diamond rod is a rod having a circular, elliptical, oval, triangular, quadrangular, or other polygonal cross section that appears by cutting the diamond rod in a plane perpendicular to the longitudinal direction. May be good. Specifically, the diamond rod-shaped body preferably has a square rod shape (square columnar shape) or a round bar shape (cylindrical column) in appearance. Further, the diamond rods may have the same or different cross-sectional shapes of two or more appearing by cutting the diamond rods in a plane perpendicular to the longitudinal direction. Therefore, the areas (sizes) of the two or more cross sections may be the same or different from each other.

<First cross section and maximum width W of the first cross section>
The maximum width W of the diamond rod-shaped body in the first cross-section is defined as the cross-section having the smallest area among the cross-sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction. The ratio L / W of the length L to the above is 10 or more and 30 or less. That is, the first cross section is a cross section having the smallest area among the cross sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction. Here, the diamond rod-shaped bodies may have the same or different cross-sectional shapes of two or more appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction as described above. .. Therefore, in the present specification, the "first cross section" is defined as the cross section having the smallest area among the two or more cross sections, regardless of the difference in shape and area.

Specifically, the area of the first cross section ^{is preferably 0.01 to 3.5 mm 2} , more preferably 0.03 to 2 mm ² , and further preferably 0.5 to 1 mm ^2. preferable.

Here, as a method of specifying the cross section corresponding to the first cross section among the plurality of cross sections of the diamond rod-shaped body, a method using a projector or the like can be exemplified. Specifically, the first cross section of the diamond rod-shaped body can be specified and the area of the first cross section can be obtained by measuring the outer diameter using a projector or the like.

<Ratio L / W>
The maximum width W of the diamond rod-shaped body in the first cross-section is defined as the cross-section having the smallest area among the cross-sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction. The ratio L / W of the length L to the above is 10 or more and 30 or less. The ratio L / W is preferably 15 or more and 30 or less, and more preferably 20 or more and 30 or less. As used herein, the term "high aspect ratio" means a case where the ratio L / W is 10 or more. Further, in the present specification, the "maximum width W" means the distance of the maximum line segment among the line segments connecting arbitrary two points on the outer line of the first cross section. For example, when the first cross section is circular, the diameter of the circle of the first cross section is the "maximum width W". The maximum width W of the diamond rod-shaped body can be measured by using the above-mentioned projector or the like.

[Diamond tool]
The diamond tool according to the present embodiment is preferably a diamond tool including a base metal portion and a diamond portion joined to the base metal portion. In this case, the diamond portion is made of the diamond rod-shaped body. Since the diamond tool includes a diamond portion made of the diamond rod-shaped body, breakage can be suppressed even when the aspect ratio is high, and a long life can be realized.

In the diamond tool, the diamond portion may be formed by joining the diamond rod-shaped body to the base metal portion by means such as brazing and processing the diamond rod-shaped body. In the diamond tool, any conventionally known alloy can be used as the base metal portion as the base metal portion of this type. As the material of the base metal part, cemented carbide (for example, WC-based cemented carbide, WC, as well as those containing Co or added with carbonitrides such as Ti, Ta, Nb), cermet (containing WC). In addition to Ti (C, N) -based cermet and WC, those to which iron-based metals such as Co, Ni, and Cr are added), high-speed steel (including at least W), ceramics (including WC, carbide) Titanium, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc. as the main components) and the like can be exemplified.

The diamond tools include, for example, drills, end mills, cutting tips with replaceable cutting edges for milling, cutting tips with replaceable cutting edges for turning, cutting tools such as reamers or taps, abrasion resistant tools such as dressers, grindstones, blades, bits, etc. Any of them can be used for various tools such as tools.

When the diamond tool is a cutting tool, the diamond portion includes a part of a rake face, a part of a flank, and a cutting edge consisting of a ridge line where the rake face and the flank intersect. The diamond tool can suppress breakage during machining of the work even when the diamond portion including the cutting edge has a high aspect ratio (that is, the ratio L / W is 10 or more and 30 or less). In the present specification, the "cutting edge" is composed of a part of a rake face, a part of a flank surface, and a ridge line where the rake face and the flank face intersect as described above, and is used for cutting or grinding a work material. The part that is directly involved.

Among them, when the diamond tool is a cutting tool, the diamond tool is preferably a drill. The drill preferably comprises, for example, a shank as the base metal portion and a diamond portion formed by joining the shank by means such as brazing and processing a diamond rod-shaped body. This diamond portion also includes at least the cutting edge described above. Even when the diamond portion including the cutting edge has a high aspect ratio (that is, the ratio L / W is 10 or more and 30 or less), the drill can suppress breakage during machining of the work, and thus has a long length. It is possible to realize a long life.

[Cantilever]
The cantilever according to the present embodiment is made of the diamond rod-shaped body. Since the cantilever is made of the diamond rod-like body, breakage can be suppressed even when the cantilever has a high aspect ratio (that is, the ratio L / W is 10 or more and 30 or less). Further, since the cantilever is made of the diamond rod-like body, the quality of the sound picked up from the sound groove of the record can be improved.

Specifically, the cantilever is manufactured by processing the diamond rod-shaped body into a predetermined shape as a cantilever applied to a record player by using a conventionally known method. In this case, the cantilever preferably contains a stylus. As a result, since the stylus of the cantilever is also made of a diamond rod, the quality of the sound picked up from the sound groove of the record can be further improved.

[Manufacturing method of diamond rod]
The method for producing a diamond rod-shaped body according to the present embodiment can be produced by appropriately using a conventionally known method for producing this type of diamond rod-shaped body, except for the second step and the third step described later. .. As the method for producing a diamond rod according to the present embodiment, it is preferable to use the following method from the viewpoint of producing the diamond rod made of CVD single crystal diamond having the above-mentioned effect with good yield.

That is, as a method for producing the diamond rod-shaped body, a conductive layer is formed on the surface of the single crystal substrate by preparing a single crystal substrate made of diamond (first step) and injecting ions into the single crystal substrate. Steps (second step), epitaxial growth of an epitaxial growth layer made of CVD single crystal diamond on the conductive layer (third step), and separation of the epitaxial growth layer from the single crystal substrate (fourth step). A manufacturing method including a step (fifth step) of obtaining a diamond rod-shaped body made of a CVD single crystal diamond by grinding or polishing a CVD single crystal diamond which is a separated epitaxial growth layer can be mentioned.

<First step>
The first step is a step of preparing a single crystal substrate made of diamond. As the single crystal substrate made of diamond, a conventionally known one can be used. For example, the above-mentioned single crystal substrate can be prepared by using a single crystal substrate (type: Ib) having a flat plate shape and made of diamond manufactured by a high-temperature and high-pressure synthesis method.

The single crystal substrate is preferably a flat plate having a surface made of (100) planes of single crystal diamond and side surfaces made of (001) planes and (011) planes perpendicular to the surfaces. Further, in the single crystal substrate, the variation in the thickness of the flat plate is preferably 10% or less. It is also preferable that the surface of the single crystal substrate has a surface roughness Ra of 30 nm or less. The shape of the surface (upper surface) of the single crystal substrate may be a rectangular shape such as a square or a rectangle, or a polygonal shape other than a rectangle such as a hexagon or an octagon.

The surface of the single crystal substrate is preferably a (100) plane as described above, and more preferably a plane having an off angle of 0.5 ° or more and 0.7 ° or less with respect to the (100) plane. preferable. However, in the present specification, the "(100) plane" of a single crystal diamond refers to a plane of a single crystal diamond whose off angle is within ± 7 ° from the (100) plane. It is referred to as "(100) plane". Similarly, the "(001) plane" and "(011) plane" perpendicular to the surface of the (100) plane of the single crystal diamond have an off angle of ± 7 ° from the (001) plane and the (011) plane. If the planes are within, these are referred to as the "(001) plane" and the "(011) plane" of the single crystal diamond, respectively.

Further, it is preferable that etching is performed on the surface of the single crystal substrate. For example, the surface of the single crystal substrate is etched by reactive ion etching (RIE) using _{oxygen (O 2} ) gas and carbon tetrafluoride (CF _{4) gas.} The etching method is not limited to the above-mentioned RIE, and may be, for example, sputtering using a gas mainly composed of argon (Ar) gas. This makes it possible to efficiently epitaxially grow CVD single crystal diamond on the surface of the single crystal substrate in the third step described later.

<Second step>
The second step is a step of forming a conductive layer on the surface of the single crystal substrate by implanting ions into the single crystal substrate. Specifically, in this step, carbon (C) ions are injected toward the surface of the single crystal substrate etched as described above. Thereby, the conductive layer can be formed in the region including the surface of the single crystal substrate. The injected ion is not limited to the carbon ion, and may be a nitrogen ion, a silicon ion, a phosphorus ion, or a sulfur ion. Here, the single crystal substrate on which the conductive layer is formed is polished using a polishing machine or the like in which diamond abrasive grains are embedded, and the surface roughness Ra of the conductive layer is adjusted to obtain a CVD single crystal. It is possible to control the average value of the phase difference generated when the diamond is irradiated with circular polarization. Specifically, when the surface roughness Ra of the single crystal substrate having the conductive layer formed on the surface is polished to 0.5 nm or more and 100 nm or less to irradiate circular polarization in the CVD single crystal diamond. The average value of the phase difference generated in the above can be 1 nm or more and 200 nm or less.

<Third step>
The third step is a step of epitaxially growing an epitaxial growth layer made of CVD single crystal diamond on the conductive layer. In this step, specifically, a single crystal in which the conductive layer is formed in a CVD furnace in which an atmosphere is formed by introducing _{hydrogen (H 2} ) gas, methane (CH ₄ ) gas, and nitrogen (N _{2) gas.} The substrate is placed and the microwave plasma CVD method is executed in the above CVD furnace. As a result, the CVD single crystal diamond can be epitaxially grown through the conductive layer, and thus the epitaxial growth layer can be formed on the conductive layer. The method for forming the growth layer should not be limited to the microwave plasma CVD method, and for example, a thermal filament CVD method, a DC plasma method, or the like can be used. _{By adjusting the amount of nitrogen (N 2} ) gas in the atmosphere inside the CVD furnace, the average atomic concentration of nitrogen in the CVD single crystal diamond can be determined. For example, _{by adjusting the amount of nitrogen (N 2} ) gas, the nitrogen in the CVD single crystal diamond can have an average atomic concentration of 1 ppm or more and 100 ppm or less. Further, regarding the atmosphere in the CVD furnace, a gas containing other hydrocarbons such as ethane gas can be used instead of methane gas.

<4th process>
The fourth step is a step of separating the epitaxial growth layer from the single crystal substrate. In this step, specifically, the single crystal substrate and the epitaxial growth layer are separated by performing electrochemical etching on the conductive layer in the single crystal substrate. As a result, a separated epitaxial growth layer, that is, a CVD single crystal diamond can be obtained. The method for separating the epitaxial growth layer should not be limited to the above-mentioned electrochemical etching, and may be a slice using a laser, for example.

<Fifth step>
The fifth step is a step of obtaining a diamond rod-shaped body made of a CVD single crystal diamond by grinding or polishing a CVD single crystal diamond which is a separated epitaxial growth layer. Specifically, by performing a conventionally known grinding process or polishing process on the CVD single crystal diamond, the length L in the longitudinal direction is 2 mm or more and 20 mm or less, and the maximum width W in the first cross section is obtained. It is possible to obtain a diamond rod-shaped body made of a CVD single crystal diamond having a ratio L / W of the length L of 10 or more and 30 or less.

From the above, the diamond rod-shaped body according to the present embodiment can be manufactured. Such a diamond rod-like body can suppress breakage of the tool even when a tool having a high aspect ratio is formed by applying the diamond rod-shaped body as a tool material, thereby extending the life of the tool. can do.

[Diamond tool manufacturing method]
The diamond tool according to the present embodiment can be manufactured by a conventionally known method as long as the diamond rod-shaped body manufactured as described above is used. For example, when a diamond tool is composed of a base metal portion and a diamond portion, the diamond rod-shaped body is joined to the base metal portion via a waxing means such as silver wax using, for example, a known clamping means, and then the diamond rod-shaped body is formed. It can be obtained by processing the body into a diamond portion including a cutting edge having a desired shape by using a conventionally known grinding process or polishing process.

[Manufacturing method of cantilever]
The cantilever according to the present embodiment can be manufactured by a conventionally known method as long as it consists of the diamond rod-shaped body manufactured as described above. For example, it can be obtained by processing the diamond rod-shaped body into a shape suitable for use in a record player by using a conventionally known grinding process or polishing process. In this case, the cantilever is preferably processed into a shape including a stylus.

[Additional Notes]
The above description includes the embodiments described below.

<Appendix 1>
A diamond rod made of CVD single crystal diamond.
The diamond rod-like body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less.
The diamond rod-shaped body has a cross section having the smallest area among the cross-sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction as the first cross section.
A diamond rod-like body having a ratio L / W of the length L to the maximum width W in the first cross section of 10 or more and 30 or less.

<Appendix 2>
The diamond rod-shaped body according to Appendix 1, wherein the length L of the diamond rod-shaped body in the longitudinal direction is 5 mm or more and 15 mm or less, or 8 mm or more and 15 mm or less.

<Appendix 3>
The diamond rod is selected from the group consisting of a circular, elliptical, oval, triangular, quadrangular and other polygons having a cross section formed by cutting the diamond rod in a plane perpendicular to the longitudinal direction. The diamond rod-shaped body according to Appendix 1 or Appendix 2, which has one shape.

<Appendix 4>
The area of the first cross section is 0.01 to 3.5 mm ² , or 0.03 to 2 mm ² , or 0.5 to 1 mm ² , according to any one of Appendix 1 to Appendix 3. The diamond rod of the description.

<Appendix 5>
The diamond rod shape according to any one of Appendix 1 to Appendix 4, wherein the ratio L / W of the length L to the maximum width W in the first cross section is 15 or more and 30 or less, or 20 or more and 30 or less. body.

<Appendix 6>
The diamond rod-shaped body according to any one of Supplementary note 1 to Supplementary note 5, wherein the average atomic concentration of nitrogen contained in the CVD single crystal diamond is 20 ppm or more and 50 ppm or less.

<Appendix 7>
The diamond rod-shaped body according to any one of Supplementary note 1 to Supplementary note 6, wherein the CVD single crystal diamond has an average value of a phase difference of 50 nm or more and 100 nm or less.

<Appendix 8>
A diamond rod made of CVD single crystal diamond.
The diamond rod-like body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less.
The diamond rod has a first cross section and has a first cross section.
The first cross section is a cross section having the smallest area among the cross sections appearing by cutting the diamond rod in a plane perpendicular to the longitudinal direction.
The diamond rod has a ratio L / W of 10 or more and 30 or less.
The ratio L / W is a ratio of the length L to the maximum width W in the first cross section, which is a diamond rod-shaped body.

<Appendix 9>
The diamond rod-shaped body according to Appendix 8, wherein the CVD single crystal diamond has an average atomic concentration of nitrogen of 1 ppm or more and 100 ppm or less.

Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited thereto.

[Example 1]
In Example 1 described below, a diamond rod-shaped body produced by the CVD method of Sample 4, Sample 6, Sample 8, Sample 9, and Sample 11 and a diamond tool containing the same correspond to Examples. On the other hand, a diamond rod-shaped body produced by a high-temperature and high-pressure synthesis method of Sample 1, Sample 3, Sample 5, Sample 7, and Sample 10 and a diamond tool containing the same correspond to Comparative Examples. Further, a diamond rod-shaped body produced by the CVD method of Sample 2 and Sample 12, and a diamond tool including the diamond rod-shaped body thereof also correspond to Comparative Examples.

[Sample 1, Sample 3, Sample 5, Sample 7, Sample 10]
<Making a diamond rod>
By executing a conventionally known high-temperature and high-pressure synthesis method, five rectangular parallelepiped-shaped single crystal diamonds (hereinafter, also referred to as "high-temperature and high-pressure diamonds") having a length of 1 mm, a width of 15 mm, and a thickness of 0.7 mm were produced. The average atomic concentration of nitrogen in the high-temperature and high-pressure diamond was measured by the above-mentioned method using SIMS and found to be 150 ppm. Further, when the average value (strain amount) of the phase difference was obtained by the above method, it was 150 nm.

By performing conventionally known polishing processes on the above high-temperature and high-pressure diamonds, a diamond rod-shaped body (sample 1) having a diameter (maximum width W) of 0.1 mm × a total length (length L) of 0.6 mm and a diameter (maximum). Significant W) 0.5 mm x total length (length L) 5 mm diamond rod (sample 3), diameter (maximum width W) 0.5 mm x total length (length L) 8 mm diamond rod (sample 5), diameter (Maximum width W) 0.1 mm × total length (length L) 2 mm diamond rod (sample 7) and diameter (maximum width W) 0.5 mm × total length (length L) 15 mm diamond rod (sample 10) Got

<Making diamond tools>
Each of the above diamond rods is fixed using a known clamping device, brazed to a cemented carbide shank which is a base metal portion with silver wax, and then the diamond rods are ground by a conventionally known grinding process. It was processed into a diamond portion including a cutting edge having a predetermined drill shape. As a result, a diamond tool (drill) for Sample 1, Sample 3, Sample 5, Sample 7, and Sample 10 was obtained.

[Sample 2, Sample 4, Sample 6, Sample 8, Sample 11 and Sample 12]
<Making a diamond rod>
(First step)
By executing a conventionally known high-temperature and high-pressure synthesis method, six diamond single crystal substrates having a flat plate shape of 1 mm in length × 15 mm in width × 0.7 mm in thickness were prepared. The surfaces of these single crystal substrates were etched by RIE to a depth region of 0.3 μm from the surface.

(Second step)
Next, carbon ions were injected at an energy of 3 MeV and a dose amount of 3.0 × 10 ¹⁶ / cm ² , to form a conductive layer on the surface of the diamond single crystal substrate. At this time, the surface roughness Ra of the conductive layer was adjusted by polishing the single crystal substrate on which the conductive layer was formed on the surface using a polishing machine in which diamond abrasive grains were embedded.

(Third step)
Further, a microwave plasma CVD method was carried out, and an epitaxial growth layer made of a CVD single crystal diamond having a thickness of 1 mm was epitaxially grown on the conductive layer of the diamond single crystal substrate. At this time, hydrogen gas, methane gas, and nitrogen gas were used as the atmosphere in the CVD furnace, and the content of nitrogen atoms in the epitaxial growth layer was determined by adjusting the amount _{of nitrogen (N 2) gas with respect to methane gas.}

(4th step)
Next, the CVD single crystal diamond as the epitaxial growth layer was separated from the diamond single crystal substrate by performing electrochemical etching on the conductive layer in the diamond single crystal substrate. The average atomic concentration of nitrogen in the CVD single crystal diamond was measured by the above method using SIMS and found to be 24 ppm. Further, when the average value (strain amount) of the phase difference was obtained by the above method, it was 68 nm.

(Fifth step)
By executing a conventionally known polishing process on the above CVD single crystal diamond, a diamond rod-shaped body (sample 2) having a diameter (maximum width W) of 0.1 mm × a total length (length L) of 0.6 mm and a diameter (sample 2) Maximum width W) 0.5 mm x total length (length L) 5 mm diamond rod (sample 4), diameter (maximum width W) 0.5 mm x total length (length L) 8 mm diamond rod (sample 6), A diamond rod (sample 8) having a diameter (maximum width W) of 0.1 mm x a total length (length L) of 2 mm, and a diamond rod (sample 11) having a diameter (maximum width W) of 0.5 mm x a total length (length L) of 15 mm. ), And a diamond rod-shaped body (sample 12) having a diameter (maximum width W) of 0.5 mm and a total length (length L) of 20 mm was obtained.

<Making diamond tools>
By executing the same method as the method for producing the diamond tools of Sample 1, Sample 3, Sample 5, Sample 7, and Sample 10 for each of the above diamond rods, Sample 2, Sample 4, Sample 6, and Sample 8 can be used. The diamond tools (drills) of Sample 11 and Sample 12 were obtained.

[Sample 9]
<Making a diamond rod>
In the first step, one diamond single crystal substrate having a flat plate shape of 1 mm in length × 15 mm in width × 0.7 mm in thickness is prepared, and in the third step, nitrogen (N ₂ ) gas with respect to methane gas is used as the atmosphere in the CVD furnace. A diamond rod (Sample 9) having a diameter (maximum width W) of 0.1 mm and a total length (length L) of 2 mm was obtained by the same manufacturing method as the diamond rod of Sample 8 except that the amount was changed. .. The average atomic concentration of nitrogen in the diamond rod was measured by the above method using SIMS and found to be 0.6 ppm. Further, when the average value (strain amount) of the phase difference was obtained by the above method, it was 53 nm.

<Making diamond tools>
The diamond tool (drill) of Sample 9 was obtained by executing the same method as the method for producing the diamond tool of Sample 8 on the diamond rod-shaped body.

<Cutting test>
Using the diamond tools of Samples 1 to 12, drilling was performed on an alumina plate (thickness: 1 mm) as a work under the conditions shown below. Each diamond is observed by observing the cutting edge of each diamond tool with an optical microscope (trade name: "VHX-5000", manufactured by KEYENCE CORPORATION) at a magnification of 100 times every 50 times of hole drilling. It was confirmed whether or not the tool was broken, and the machining performance (number of times that the tool could be machined) was evaluated. The results are shown in Table 1. In the item of "evaluation" in Table 1, when comparing with a diamond tool having a diamond part having the same ratio L / W, the sample that has been drilled a larger number of times is expressed as "excellent" and less. Samples that have been drilled a number of times are labeled as "inferior." It can be understood that the sample (diamond tool) evaluated as "excellent" has a long life. Further, in Table 1, the diameter (maximum width W), total length (length L) and ratio L / W of the diamond part of the diamond tools of Samples 1 to 12, the appearance shape of each diamond tool, the type of diamond part, and the nitrogen. The average atomic concentration and average phase difference are also described.

(Conditions for hole processing)
Work: Alumina plate (thickness: 1 mm)
Processing equipment: UVM-430 (Toshiba Machine Co., Ltd.)
Drill speed: 30,000 / min
Feed rate: 10 mm / min
Cutting oil material: Oil mist (wet).

(Discussion)
Both the diamond tool of sample 1 and the diamond tool of sample 2 had a ratio L / W of less than 10, and the alumina plate could not be drilled. On the other hand, the diamond tool of sample 3 and the diamond tool of sample 4 both have a ratio of L / W of 10, but the diamond tool of sample 4 is processed more frequently than the diamond tool of sample 3 and has a long life. It was transformed. Further, the diamond tool of sample 5 and the diamond tool of sample 6 both have a ratio L / W of 16, but the diamond tool of sample 6 is processed more frequently than the diamond tool of sample 5, and the life is extended. It had been.

The diamond tool of sample 7, the diamond tool of sample 8, and the diamond tool of sample 9 all have a ratio L / W of 20, but the number of times the diamond tool of sample 8 and 9 is processed is larger than that of the diamond tool of sample 7. There were many cases, and the life was extended. The diamond tool of sample 10 and the diamond tool of sample 11 both have a ratio of L / W of 30, but the diamond tool of sample 11 is processed more frequently than the diamond tool of sample 10, and the life is extended. Was there. The diamond tool of sample 12 had a ratio L / W of more than 30, and was broken after 50 times of hole drilling.

From the above, the diamond rods of Sample 2, Sample 4, Sample 6, Sample 8, Sample 9 and Sample 11, and the diamond tool including them are suppressed from being broken when the workpiece is processed, and thus the life is extended. Is understood.

[Example 2]
<Making a diamond rod>
The diamond rod of this example was prepared by using the same method as the diamond rod of sample 4 in Example 1.

<Making a cantilever>
A cantilever containing a stylus was obtained by performing a conventionally known grinding process on the diamond rod-shaped body. This cantilever had a shape of (maximum width W) 0.5 mm × (length L) 5 mm. The needle tip length of the stylus formed on the free end side of the cantilever was 0.1 mm. The maximum width W of the cantilever was measured at the stylus portion.

When the above cantilever was applied to a known record player, a good tone could be picked up from the sound groove formed in the record.

Although the embodiments and examples of the present disclosure have been described as described above, it is planned from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined or variously modified. ..

It should be considered that the embodiments and examples disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the embodiments and examples described above, and is intended to include meaning equivalent to the scope of claims and all modifications within the scope.

Claims (7)

1. A diamond rod made of CVD single crystal diamond.
   The diamond rod-like body has a length L in the longitudinal direction of 2 mm or more and 20 mm or less.
   The diamond rod-shaped body has a cross section having the smallest area among the cross-sections appearing by cutting the diamond rod-shaped body in a plane perpendicular to the longitudinal direction as the first cross section.
   A diamond rod-like body having a ratio L / W of the length L to the maximum width W in the first cross section of 10 or more and 30 or less.
2. The diamond rod-shaped body according to claim 1, wherein the average atomic concentration of nitrogen contained in the CVD single crystal diamond is 1 ppm or more and 100 ppm or less.
3. The CVD single crystal diamond has an average value of phase difference of 1 nm or more and 200 nm or less.
   The diamond rod-shaped body according to claim 1 or 2, wherein the phase difference is a phase difference generated when the CVD single crystal diamond is irradiated with circular polarization.
4. A diamond tool including a base metal portion and a diamond portion joined to the base metal portion.
   The diamond part is a diamond tool made of the diamond rod-shaped body according to any one of claims 1 to 3.
5. The diamond tool according to claim 4, wherein the diamond tool is a drill.
6. A cantilever made of the diamond rod-shaped body according to any one of claims 1 to 3.
7. The cantilever according to claim 6, wherein the cantilever includes a stylus.